Commercially and clinically, silicone hydrogel contact lenses are a popular alternative to conventional hydrogel contact lenses (i.e., hydrogel contact lenses that do not contain silicon or silicon-containing ingredients). Over the past decade, the use of silicone hydrogel contact lenses has steadily increased due in large part to their higher levels of oxygen permeability as compared to conventional hydrogel materials, allowing greater concentrations of oxygen to reach the cornea during wear. While the siloxane monomers present in the lens formulations result in the higher levels of oxygen permeability, these hydrophobic monomers also limit the types and amounts of other ingredients which can be combined to form miscible polymerizable compositions that polymerizes to form clear polymer lens bodies free of unwanted color.
Increasing competition in the field of silicone hydrogel contact lenses demands that new lenses be developed having new or improved properties. For example, there is interest in developing anti-microbial contact lenses to reduce the incidence of bacterial infection in the eye, anti-allergy contact lenses for lens wearers who suffer from seasonal allergies, contact lenses having wetting agents attached to the lens for lens wearers who suffer from dry eye conditions, etc.
One method of providing conventional hydrogel contact lenses with new or improved properties has been described in International Publication No. WO 93/00391, which is incorporated herein in its entirety. WO 93/00391 describes polymeric substrates having functional groups in the substrate polymer chain, and reacting the functional groups with complementary functional groups on a hydrophilic coating polymer in a predominately aqueous medium to form covalent linkages between the coating polymer and the substrate polymer.
Examples of lens formulations comprising a primary amine-containing monomer can be found in Example 18 of U.S. Patent Application Publication No. US 2012/0026457, which is incorporated herein in its entirety. The polymerizable compositions of lens formulations D1, D2 and D3 of Example 18 of US 2012/0026457 each contains less than 20 wt. % of hydrophilic monomer.
There is a need for new silicone hydrogel contact lenses with favorable properties such as relatively high water contents, relatively high levels of oxygen permeability, and ophthalmically acceptable modulii, new polymerizable compositions for forming silicone hydrogel contact lenses which comprise relatively high amounts of hydrophilic monomers and siloxane monomers, and new methods of manufacturing silicone hydrogel contact lenses which allow various types of agents to be attached to the lenses to modify the lenses under conditions which are acceptable for manufacturing of a medical device, are needed.